Homs residents cut off from world, Senegal professors skipping out on classes, and more...

This show is made up entirely of amateur images. We've seen time and time again how images captured by ordinary citizens then uploaded onto the Web can change history, or at least shift the balance of power. This week, we take a look back at some of those moments.

STORY 1: SYRIA

We begin once again today in Homs. It is Syria's third-largest city, but it's known to the world as the focus of Bashar al Assad's brutal crackdown on opponents of his regime. Since early February Assad's forces have been pounding the Baba Amr neighborhood with artillery. Activists say they shoot at anyone who goes in the street. The siege has made communication very difficult. When we call our contacts in the city, the phones just don't work. But one group of activists has managed to smuggle a satellite internet connection into the city. That's how we got in touch with our Observer, Khaled Abu Salah.

STORY 2: SENEGAL

Now to Senegal - the capital Dakar, and its huge Université Cheikh Anta Diop, named for the famous anthropologist. The university has more than 60,000 students, and for the time being, they're doing nothing. Their professors are on strike. There's also a nationwide election going on, and that hasn't helped things. Here's Médoune Fall, one of the frustrated students.

STORY 3: WORLD

Now for our weekly roundup of the best images and stories sent in by our Observers.
First stop, Johannesburg, and a "Miniskirt March" to draw attention to sexual violence against women. It's a huge problem for young women in South Africa. Four in 10 women aged 13 to 23 report having been harassed - or worse - at social events or in the street. In one recent incident two women were taunted and groped by a group of 60 men at a taxi stand. One of the women was wearing a miniskirt, but that - says our Observer Troy - is no excuse: in a free South Africa, women should be able to wear what they want.

Our last stop is Moscow, where protests against Prime Minister Vladimr Putin are going into overdrive. People who don't like the idea of Putin becoming president for a second time have had a hard time getting permits to hold rallies. So they've decided to demonstrate in their cars, by honking their horns and displaying white ribbons and balloons - symbols of the opposition. Our Observer Pavel says the police don't intervene - meaning it's an easy way for first-timers to join the protests